It sounds like you have a low battery. Even though it will start sometimes doesn't mean the battery is ok. Low voltage to the electronic modules that control different function can cause all sorts of strange things to happen, including flashing lights. I don't know if you will need a new battery or not. It will need to be fully charged(if possiable) and tested. The charging system slso needs to be tested. It's possiable that it wasn't charging the battery. Take the battery to your parts store. They can charge it & check it. Put either new or old battery in. Start car let warm up. turn on all accessories to load up the system. Check across battery terminals voltage should be 13.5 to 14.5. If not either the alt. is bad or the regulator circuit is not working. It is controled by the computer for gas mileage increase. The alt. can be removed and bench tested at your parts store. If ok a shop would be better to check the computer circuit that regulates charging system. If you decied you want to tackle it ,I can send you the test. hope this helps you out. Please accept my answer if your satisfied. Thanks 32dmadden